Lawn mower sharpener



` of. 13, 1942. AL SILFEN 2,298,978

LAWN MOWER SHARPENER Filed May 26, 1941 Patented Oct. 13, 1942 UNITED STATES PATENT oFFicE LAWN MOWER SHARPENER Alfred Silfen, Berkeley, Ill.

Application May 26, 194-1, Serial No. 395,193

e (C1. vs -82.1) v

4 Claims.

The present invention relates generally to sharpeners for lawn mowers. More particularly the invention relates to that type of lawn mower sharpener which comprises a metallic bar with abutment or contacting relation with one of the spiral blades of the rotor, and then grasping the ends of the bar and shifting the bar back and forth between the wheels of the lawn mower in order to cause the le tor move lengthwise of the one blade and sharpen the latter.

One object of the invention is to provide a lawn mower sharpener of this type which is an improvement upon, and has certain advantages over, previously designed Sharpeners of the same general character, including that which is shown in, and forms the subject matter of, an application for United States Letters Patent filed by me on March 10, 1941, Serial No. 382,508.

Another object of the invention is to provide a lawn mower sharpener of the type under consideration in which the file retaining bracket is of new and improved design and is so constructed that when it is in assembled and locked relation with the bar the file is effectively and efciently locked against longitudinal or transverse movement with respect to the bar.

A further object of the invention is to provide a lawn mower sharpener of the last mentioned character in which the bracket'l consists of a U- shaped clip in straddled relation with the bar and in addition a screw carrying cross piece over the bar and in interlocked relation with the side legs of the clip and embodies novel means at the sides of the file for receiving the blade to be sharpened and causing the blade in connection with reciprocation or back and forth movement of the bar between the lawn mower wheels to rotate rst backwards and then forwards.

A still further object of the invention is to provide a lawn mower sharpener which is both practical and durable and in which facility of adjustment is combined with simplicity of design or construction.

Other objects of the invention andthe various advantages and characteristics of the present lawn mower sharpener will be apparent from a consideration of the following detailed description.

The invention consists in the several novel features which are hereinafter set forth and are more particularly defined by claims at the conclusion hereof.

In the drawing which accompanies and forms a part of this specification or disclosure and in which like letters and numerals of reference denote corresponding parts throughout the several views: y

Figure 1 is a plan view of a lawn mower having applied thereto a sharpener embodying the invention;

Figure 2y is a vertical transverse section taken on the line 2-2 of Figure 1 and showing the sharpener in its operative or blade sharpening position;

Figure 3 is a perspective view of the sharpener illustrating the construction of the bar and showing in detail the arrangement and design of the file retaining bracket;

Figure 4 is a perspective view of the U-shaped clip of the bracket;

Figure 5 is a perspective view of the screw carrying cross piece of the bracket; and

Figure 6 is a perspective of the file.

The sharpener which is shown or illustrated 'g in the drawing constitutes the preferred embodiment of the invention. It is illustrated in connection with a conventional or standard lawn mower L and serves, as hereinafter described, as a medium for sharpening the blades of the lawn mower. The lawn mower L comprises a horizontally extending rotor I, a pair of ground wheels I1 at the ends of the rotor, and a handle I2. Gearing (not shown) in housings I3 serves to drive the rotor from the wheels during forward movement or travel of the lawn mower. In addition to the aforementioned parts the lawn mower comprises a tie rod I4between the gear housings I3 and a xed horizontally extending knife bar I5. The rotor is provided with a plurality of equidistantly spaced spiral blades I6 and these, as well understood in the art, are adapted or designed in connection with forward travel of the lawn mower successively to traverse the knife bar I5 and effect the desired cutting of the grass. The

'- knife bar is located at the bottom of the lawn piece metallic bar 'I and a longitudinally adjustable bracket 8 on one end of the bar. As hereinafter described the bracket serves as a retainer for a iile 9.

The bar 'I is formed of at metal stock and is adapted in connection with use of the sharpener to be placed in a transverse position over the lawn mower rotor, as shown in Figures 1 and 2. It consists of a straight short end part I0, a, straight long end part II and a U-shaped guide I2 between the two end parts. The guide is formed by striking upwards or otherwise shaping the portion of the bar that is directly inwards of the short end part I and serves as a medium for connecting the two end parts I0 and II. It is adapted in connection with use of the Sharpener to straddle and slide lengthwise of the tie rod I4 -of the lawn mower L and has a, pinisupported roller I3 beneath the cross piece thereofz .When the Sharpener is in use the roller I3 rides' upon the upper portion of the tie rodl4 and .thuslpers mits the guide to travel freely along the tie rod.

The outer extremities I0 and I I of the bar are bent upwards ,to form handles I4 whereby-the bar may be gripped between the thumb and forengers when itx is :shifted back f 'and' forth `for hladesharpening purposes; rf r f The bracket surroundsand is slidable lengthwise of the straight long end part l-IIv-oflthebar 1; It serves in-addition toholdingorzretaining the le Seto-guide the .bladetobe:sharpenedrwith respect tothe le and'comprisesaiU-shaped'clip I5 and a cross piece|6zfff1`hefclip I5fisiir1'thel form of a one-piece sheet metal stamping and is arranged instraddled-relation:with the' long end part Hiof the'bar 'has shown'in'liigures 2fand3.` It serves as the le retaining instrumentalityof' the` bracket 8 and vconsists of` a cross. legal? r and a. pairnofzupstandingsidelegs |8.---:The-.cross leg extends :between and serves .:to connectxtheatwol side legs. It ts slidably against the bottomi-face of ,thewstraight long vendpartfI I of the'barilwhen the .fbracketziisfin' assembled `relation With-the bar and has acentralslot119.'.- `4This slotz'extends transversely of the bar end part IIzandisparallel to the side edges ofthe Vcross .leg I'Lf It is .adapted to receive the edge of the blade to besharpened, as shownY in Figure 2; :lts `ends terminatei'at-the junctures of thetcross legandthezsi'deflegs.- rThe portions of .the .fcross: leg` Whichcdenet t-heY sides of. :the slot are pressedl or` struck fdownwardsl .'to forma pair of:y shallow foppositely; facing'zseats 20 which" serve as supporting means; for the side margins of theale 9. and have; shoulders 2 Ialong. their iouter side'lportions. Theyare'falsoishaped to 'forma pair. of semicircularopposed guidelugs 22.' 'Whent in assembled relationzwith'the bracket the le Stoverlies: the` slot. .IQJini'the'scentral por-4 tion; of; the cross legll :of ther'clip I5 and `rests uponp-andlis :supported by, the seats `'20."1'Ihe width ofthe leqcorresponds 'tofthe distance. between the :two shouldersy 2 I. with the result that the sideedgesoft-hele abut againstthe shoul-l ders .2I.and..coact -therewith to 1hold` .the4 le againstjlatera'l displacement .with respect to the clip I5. The guide lugs 22 are adapted to straddle'the blade tobe sharpened, as illustrated in Figure 2. They have ia" twofold purpose. vin that they serve, rlrst, `to hold the bladeto" be sharpenedK ina'butment with` 'the l"bottom faceY of the' iile 9 when'- the Sharpener Lis usedI and; secondly, tocause `the blade to line-sharpened l in; connection with vreciprocationorfback V*and `forth movement of--the bar. between. the lawn mower wheels toro# tateor swing rstobackwards andlth'err' forwards. By` reason`A 'of'fith'e vfa'ctzthat the'- guide lugs 22r are semici-rcularrthey slide readily= against? the fside I f l 1' manner that the file is heldfagair'istlongitudiiial faces of the blade to be sharpened during a sharpening operation. As shown in Figure 2 the guide lugs are downwardly inclined to a slight extent. As a result of this they are in spaced relation with respect to the bottom face of the file 9 and there is no likelihood of the blade to be sharpened becoming bound between them in connection with back and forth shift or reciprocation of the bar 1.

The side legs I8 of the U-shaped clip I5 extend upwards at rightfangles to'theoross leg I'I. They lap and sldably engage the `side." edges of the straight long end part II of the bar 'I and have central wedge shaped openings 23. Preferably there is but a minimum amount of clearance f between'the'- side legs I8 and the side edges of thebar end part II and as a result when the bracket is in assembled relation with the bar thel side legs. hold the bracket against tilting movement with respect to the end part II. The openings'-23 in the central portions of the side legsfare so designed or shaped tlratthesmall ends :thereof Y-are at Ythe bottoni `and 2joinfand communicate with tl'ie -e'nds fof the centralnot'ch' I9I in the'` c'ross Aleg '-IIf'f The yportions-offthe side legs I8 which dene the upper"or`-l`arg`ef ends of ithe "openings E231-haveLz downwardly. Tracing notches24.=-- These notches are o'i materiallyfless width than the uppe'rrendsfoff the open-ingsi23 and join and communicate with the upper 'ends' of said-'openings.= The' lower'flnner'- corner 'p tionsofthe' side legs "-I 8; Vthatwisgl the E*portions which denne the lowerendsof Ythewefslg'e"shaped openings 23;- extend across the ends 'ofthe se'ats' 20 -iandlengage the? corners of fthe 1 fileB- insucli Ped - sheetmetalfstamping an'dfislflat sldedl-l'fAs shown -g piece are adapted 't'oproject`- through lth central prevent longitudinalifdispIacnetl'offthe cross" piece-with respecta the "clip: centrar prtioiiof'tlie crdss'lpiec'el is provided'` withavertical orf-'transverse"internally threaded hole `2'I," fo'r`a clamp screw-28.' The'inn'eror"loir-lerA end ofrth screw is adapted toabut against the'topdfalce ofV the straight long end part I If'f the-bar Ig and-the 0uter`en'd of the screw is provided with la flattened head 29 in order that the screw-maybe A readily turned. Whenf the -screw -is-tightened aaeaevs whole thus adjusted for use in connection with different Sized lawn mowers.

In assembling the bracket 8 the file 9 is first placed over the central portion of the cross leg I1 of the U-shaped clip I5 and is then urged or pressed downwards into seated relation with the seats 20. Thereafter the clip is manipulated into straddled relation with the straight long end part II of the bar l. After the latter operation the cross piece I6 is placed over the top face of the end part I I and is manipulated so as to bring the ends thereof into interfitting relation with the notches 24 in the upper central portions of said legs I8 of the clip. At the conclusion of this operation the screw 28 is tightened so as to clamp the bracket to the long end part II of the bar. In using the Sharpener the bar 'I is manipulated so as to bring the U-shaped guide I2 into straddled relation with the tie rod I4. After proper positioning or manipulation of the guide the bracket 8 is adjusted and then manipulated so as to bring the blade to be sharpened between the guide lugs 22 and into abutment with the bottom face of the file 9. When the Sharpener is properly positioned the handles I4 at the outer extremities of the bar 1 are grasped and the bar is shifted back and forth between the wheels of the lawn mower L. During such movement of the bar the file 9 engages and slides along the edge of the blade to be sharpened and effects the desired sharpening. After sharpening of one blade of the rotor the Sharpener is used to sharpen the other blades. If it should be necessary to change the file due to wear the screw 28 is loosened so as to release the bracket 8. After release of the bracket the cross piece I6 is removed from the clip so as to free the latter and permit the file to be removed from seated relation with the seats 20.

The herein described lawn mower Sharpener consists of but a small number of parts and hence may be manufactured at a low and reasonable cost. It is durable or rugged and is characterized by the fact that the construction and design of the bracket 8 are such that the Sharpener as a whole is extremely efficient in operation and may be used with facility.

The invention is not to be understood as restricted to the details set forth since these may be modified within the scope of the appended claims without departing from the spirit and scope of the invention.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

l. A bracket and file assembly adapted to form w a part of a lawn mower Sharpener of the bar type and comprising a bracket slidably mounted on one end of the bar and consisting of a U-shaped clip embodying a cross leg fitting against the bottom face of said one end of the bar and having a lawn mower blade receiving guide slot in its central portion and the portions thereof that define the sides of the slot depressed to form a pair of opposed seats above the slot, and also embodying a pair of upstanding side legs projecting upwardly from the ends of the cross leg and above the Side edges of said vone end of the bar and having opposed openings in the central portions thereof, and a cross piece over said one end of the bar having its ends extending through the openings in said side legs of the clip, and provided at its central portion with bar engaging means for urging it and the clip upwards relatively to said other end of the bar, and an elongated blade sharpening file over the guide slot, extending transversely across the bottom face of said one end of the bar and having the side margins thereof fitting snugly within the seats.

2. A bracket and le assembly adapted to form a part of a lawn mower Sharpener of the bar type and lcomprising a bracket slidably mounted on one end of the bar and consisting of a U-shaped stamped metal clip embodying a cross leg tting against the bottom face of said one end of the bar and having a lawn mower blade receiving longitudinally extending guide Slot in its central portion and the narrow marginal portions thereof that define the sides of the slot depressed to form a pair of opposed seats above the slot and with shoulders at the sides thereof and also shaped to form a pair of inwardly extending opposed substantially semicircular blade receiving guide lugs, and also embodying a pair of upstanding side legs projecting upwardly from the ends of the cross leg and above the side edges of said one end of the bar and having opposed openings in the central portions thereof, and a cross piece over Said one end of the bar having its ends extending through the openings in said side legs of the clip, and provided at its central portion with bar engaging means for urging it and the clip upwards relatively to said one end of the bar, and an elongated blade sharpening file over the guide slot, extending transversely across the bottom face of said one end of the bar and having the side margins thereof iittiing snugly within the seats and against said shoulders.

3. A bracket and file assembly adapted to form a part of a lawn mower Sharpener of the bar type and comprising a bracket slidably mounted on one end of the bar and consisting of a U- shaped stamped metal clip embodying a cross leg fitting against the bottom face of said one end of the bar and having a longitudinal lawn mower blade receiving guide Slot in its central portion and the marginal portions thereof that define the sides of the Slo-t depressed to form a pair of opposed seats above the slot with shoulders at the sides thereof and shaped to form a pair of inwardly extending downwardly inclined blade engaging guide lugs beneath and inwardly of the seats, and also embodying a pair of upstanding side legs projecting upwardly from the ends of the cross leg and above the side edges of said one end of the bar and having opposed openings in the central portions thereof, and a stamped metal cross piece over said one end of the bar having head equipped ends extending through the openings in, and interlocked with, said side legs of the clip and provided at its central portion with bar engaging means for urging it and the clip upwards relatively to said one end of the bar, and an elongated blade sharpening file over the guide slot, extending transversely across the bottom face of said one end of the bar and having the side margins thereof fitting snugly within the seats and against said shoulders.

4. A bracket and file assembly adapted to form a part of a lawn mower Sharpener of the bar type and comprising a bracket slidably mounted on one end of the bar and consisting of a U- shaped clip embodying a cross leg fitting across the bottom face of said one end of the bar and having a longitudinal lawn mower blade receiving guide slot in its central portion, and also embodying a pair of upstanding side legs fitting against and projecting above the side edges of said one end of the bar and having in the cen-k trail' portions thereof Opposedfopenings together with short notches at" the.' up'p'er ends of the openings, and a cross piece over" said one` end of the bar provided at its ends with narrow necks and laterally elongated heads beyond the necks and having said necks fitting within the notchesand the heads in abutment with` the outer faces of said side legs of the clip, and a1so,p1o.

vided at its central'portion with bai: engaging means, for` urging it and the clip upwardsfrlelatively to said one end of the bar, and, a blade sharpening le extending. over said slot and fitting between the cross leg of the clip and the bottoni face of said one end of the bar.

ALFRED SILFEN.. 

